This study is the second phase of a cross-national investigation of developmental dyslexia in Italy and the United States. Assessing children in differing linguistic environments provides an opportunity to evaluate the degree to which the phonetic regularity of a language influences the prevalence and types of dyslexia. Children in a linguistic environment where dyslexia is reportedly rare and where the language shows relatively consistent grapheme-phoneme correspondence (Italy) will be compared to children in a setting where dyslexia is common and where the language is comparatively irregular (the U.S.). This will permit analysis of the interaction between phonetic-linguistic factors and individual patterns of cognitive ability. Cognitive patterns will be examined by analyzing the children's performance on a battery of neuropsychological tests assessing both auditory-verbal and visual-spatial abilities. The performances of dyslexic children will be compared to the performances of children with adequate reading skills in order to determine the proportion of dyslexics whose reading disability is related to specific deficits in verbal or spatial processing. The study will attempt to discover whether the orthographic regularity of the Italian language reduces the prevalence of dyslexia, modifies the neuropsychological characteristics of the disorder, creates a dissociation between reading comprehension and decoding, and produces a shift in the type of reading errors, when compared to American children. Understanding the effects of linguistic factors on the prevalence and pattern of reading disabilities should have direct impact on clarifying the etiology of dyslexia and should have important implications for developing strategies for remediation.